Camshaft

[David Kemp]

Is there an oversize camshaft , or way to recondition the cam bearing surface if it is worn?
Are new camshafts available?
My Jupiter cam has been sitting a long time & has rust marks, I would hate to put it into the crank case as there are no bearing shells.

[Forumadmin]

Yes. Shafts with oversize bearing journals and modified profiles have been manufactured. Whether any are now available is unlikely. Try mailing Bill Lock via JT or try JCC NZ spares.

[Chris Spencer]

Better still why not contact JCS first - they should be in a position to help you

[Mike Allfrey]

JCS may, if you are extremely lucky, have a Vernier type camshaft of dimensions for an 'Odd-Half' crankcase set. Such bearing journals could be ground to match your crankcase bores, or, combine such activity with line boring the crankcase to match. The Vernier shaft requires a matching drive sprocket.

DO NOT be tempted to machine the crankcase joint faces to 'recondition' the bearing bores. Other troubles will certainly ensue.

There is a company here in Melbourne's outer east, I think their business name is Camshaft Grinders, or similar. They showed us on a Rover Car Club visit the type of work they do. I will get back to you on that. They metal-spray and grind back bearing journals.

Cheers,

Mike A.

[David Kemp]

After reading Phill Dingles article on cams can any one recommend a cam grinder in Brisbane QLD?
Or a profile? Or what not to do?

[Mike Allfrey]

David,

It is probably best for you to contact Brian Holmes or Doug Rath in Brisbane for a local camshaft reconditioning service shop for work on your camshaft.

I do not know what Phil's article is about. However, as I get older and, maybe, more experienced I understand that everyone wants more performance out of their Jowett or whatever motor car's engine. I am, however convinced that with the Series III Javelin/Jupiter engine, and contrary to popular belief, Jowett Cars Limited 'got it absolutely right'.

Our crankcases and other major engine components are now classed, by me, as being old and tired (exhausted), so, why the desire for yet more performance? Such extra performance cannot be used on our overcrowded roads and in our police states - unless of course, you live in Longreach.

I tend to stay with the standard cam profiles, they are perfectly adequate - just like the Javelin/Jupiter front hub bearings which no one in this country, and others, seem to understand.

Do what you wish, but when disaster strikes - DO NOT BLAME JOWETT CARS LIMITED for the consequences.

For what it is worth,

Mike Allfrey.

[Chris Spencer]

Mike - I can only but fully agree with you - why anyone wants to put more power through a drivetrain & chassis beyond its design capability is beyond me - by all means make modifications that improve the car but to not make it quicker - don't get me wrong I don't want to spend all day driving a 100 miles either - I' m very happy with the 60 MPH performance of my Javelin but if I want to go quick I purchase a suitable vehicle for doing so

[Mike Allfrey]

Thanks Chris,

What you say is correct.

In my response, I meant to mention the standard grind for a Series III camshaft (with Vernier timing adjustment) - that copes with the solid tappets.

Off subject completely, I have become involved with a 1965 Ford 4000 tractor with a form of automatic transmission. It was donated to a Pastoral Society at the western end of Victoria. The society soon found out why the tractor was donated to them, both reverse gears were missing. What a can of worms! A Jowett engine ages me about five years, but this transmission is a real qualifier for ten years of aging. Those who do not know have been in there and wrecked the control cable and the starter inhibitor switch wiring. Parts are very few these days, we are better off with a Jowett!

All the best,

Mike A.

[David Kemp]

The object of the exercise is not more power , but more efficiency. The Jowett cam was designed in the 1940's, & time has moved on.
A modern profile cannot on it's own magically double power, but it can improve response , idle & torque.
The thing most notable about the Jowett cam is the symmetrical ramps on the lobes, something supposedly very old fashioned.
I drive at lower revs than most people, so should probably have a Bradford or tractor, not a Jupiter!
I spoke to Brian Holmes yesterday, who recently has had a cam change. He has given me the address of who to go to
Enoggera Cylinder heads, & who not to go to(they will remain nameless).
I hope to sort the cam out shortly, however please give advice as all ideas are very welcome.
Cam grinds are like your 1st baby. everyone has advice from their 1st child & most is conflicting, end of the day the new parent still needs to work it out the hard way, as all babies are different

[Keith Clements]

The majority of Jowett owners are satisfied, or perhaps delighted , that their Jowett starts, runs and gets them to their destination. Wishing for anything more is just dreaming.
But a few do yearn for more and want the joy of powering up a hill and keeping up with traffic on motorway. Perhaps a few more are concerned about pollution and fuel efficiency of their Jowett.
An even smaller percentage compete their Jowett and to them this discussion might be of interest. What is certain is that the Jowett profile should be changed for racing at high revs or to get good efficiency at motorway speeds with modern petrol and some gas flowing of heads. But for general use an unworn original cam will give a broad torque curve motor that just looses power at higher revs. Torque curves of my race engine on JT can be compared with the original in the tuning notes.

However, step one is to get the ignition advance curve correct. Step two is to get the jetting and mixture induction correct before doing the cam. Then you need to tune all three along with the exhaust, compression ratio, swept volume, balancing everything and hope the engine holds together.
But you should be able to get 50 per cent more power which might save the planet .

[Chris Spencer]

What's the point of having a car with 50% more power with chassis / drivetrain / suspension & braking system that is well beyond its design capability - should you be lucky enough to keep that car on the road without sticking it in a ditch or worse still impacting with a third party vehicle - pretty pointless - yes some Jowetts are used for competition with suitably upgraded drivetrains / suspension & brakes - to maintain speed on the UK motorway network you need a vehicle that can comfortably cruise at 80 MPH (although our national limit is 70 MPH very few stick to it) but you also require to stop within the distance and have the same degree of all round vision that is afforded by modern vehicles along with the inbuilt safety features - You are never going achieve this with vehicle that is 70 years old in design hence increasing power to achieve greater speed is futile - there is however a wide range of very quick & responsive modern sports cars in the market that are very capable of getting you to your destination safely - obviously that does depend on the drivers capability

[Forumadmin]

I have never had trouble stopping or cornering my Jowett at modern traffic speeds or even rally speeds. Touch wood!
It does require a bit more anticipation and consideration of braking distances when competing with ABS.
The standard engine now in my Jup, apart from DelLorto carbs, was happy to cruise at 80+ on European roads, albeit in overdrive.
You do also need to be a little sympathetic with the gearbox, but now you can have them rebuilt with modern components should you be concerned.
Keeping up with modern traffic is, in my opinion, a much safer way to drive than worrying about lorries ramming you in the back or being cut up by impatient motorists. I also find it much more enjoyable, and certainly more enjoyasble than driving at the same speed in a modern, so beg to be different.

[David Kemp]

Brian Holmes uses a BMC Mini Cooper S grind. Given both engines are Harry Weslake designs with a siamese intake port it could be a logical choice. As his engine has done over 100000 Klm and does not leak oil or water, possibly this is a good grind , it is apparently not stressing the motor.